Describe the bug
I added add_theme_support( 'disable-custom-font-sizes' ); to my theme , but the custom font sizes field still appears in my theme.
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Additional context
Hey @salamalala,
this is a feature of Gutenberg 4.1. see #10620, which is not released yet.
You can download the Release Candidate or wait a few days for the release
Ok thanks @Soean. Because it's in the handbook (https://wordpress.org/gutenberg/handbook/extensibility/theme-support/#disabling-custom-font-sizes) I assumed it would be already in the current version.
Im running 4.3.0 and neither add_theme_support( 'disable-custom-font-sizes' ) or add_theme_support( 'disable-custom-colors' ); seem to work for me
@lukehm would you be able to try with 4.4 and, if the problem is still happening for you, create a new issue and include some steps for testing? I can help test but need more explicit testing steps for technical cases where custom code is required. Walk me through it with steps and I'm keen to help test!
@designsimply Steps to reproduce, using a clean WP installation:
add_theme_support( 'disable-custom-font-sizes' );
add_theme_support( 'disable-custom-colors' );Font Size, Background Color, and Text Color are still there.
Ive done that still seeing all items

As of wordpress 5.0, disabling colors works but there is still a list of colors : we need to add_theme_support( 'editor-color-palette' ); before disabling it. Weird ?
The disabling of custom font-sizes works too but there is no way to hide the entire "text settings" block" :'(
All this functions are fired in the "after_theme_setup" action.
Most helpful comment
As of wordpress 5.0, disabling colors works but there is still a list of colors : we need to
add_theme_support( 'editor-color-palette' );before disabling it. Weird ?The disabling of custom font-sizes works too but there is no way to hide the entire "text settings" block" :'(
All this functions are fired in the "after_theme_setup" action.